[aNapierkowski]

yeah I took a look at the methodology here, it seemed like this should have been accounted for in the plan though maybe I'm missing something. That said this is just one study and will play into meta-analyses at some point which are more interesting

After the 7-day wash-in, both groups followed the same RT program that comprising 3 full-body sessions a week for 12 weeks (Supplementary Materials, Table S1). All sessions were supervised by tertiary qualified exercise physiologists and commenced with a standardised warm-up of dynamic flexibility exercises. Each session consisted of 5 exercises: 2 compound movements each for the upper and lower body, and 1 isolation movement for the upper body. Four sets were prescribed for all movements to ensure an adequate weekly training volume for hypertrophy [32]. Training intensities were 6 to 12 repetition maximums (RM) with 60 and 120 s of rest between sets and exercises, respectively. To adhere to the prescribed RM, an individual’s rating of perceived exertion (RPE) on a Likert scale of 1–10 was recorded. RPE corresponds to the number of repetitions an individual perceives they will be able to perform after the set is complete, where an RPE 5 equates to 5 reps more, RPE 6 is 4 reps more, RPE 7 is 3 reps more, and so on [33]. When a RPE of 8 or lower was recorded, the external load (kg) was adjusted on successive sets to ensure that subjects achieved the target RM. The RM method was used to ensure that training intensities were relative to the individual’s abilities while also standardising the training intensity across all participants [34].

[beezle]

A few things -

1/ on this RPE stuff, it sounds like they are trying to keep two reps in the tank which is fine but..when? the first set? The last set?

2/ perhaps I'm misreading the supplemental data but the error bars are pretty huge when it comes to changes in LBM, not sure how any conclusions can be drawn

3/ 12 weeks is a short program and it sounds like they chose people who were generally not in shape/beginners. Anyone who has lifted in their life can tell you initial gains are almost always mostly in strength, not mass.

4/ Their choice of lifts for this population also looks unusual.

I'm sure they have the data but I could not find any evaluation of relative strength gains between the two groups. Even if their hypothesis that the LBM gain is identical, strength gains may not be.

[svnt]

Their methodology does seem to potentially capture what is at question here, by use of perceived exertion to adjust weight for repetition maximums.

It is possible it doesn’t capture everything, because they don’t say anything here about setting the initial load, or adjusting the load up for low perceived exertion, only down for high perceived exertion.

[daveguy]

It seems like the protocol would detect either benefit, if present.

It makes sense that the body's adenosine re-phosphorylation is not rate limited by creatine at all (which the body produces naturally). In that case, having extra creatine lying around would just make your pee more expensive and give you a nice placebo effect from believing you can lift more. (And placebo effects are real effects, particularly for effort related tasks. Just not due to chemistry of the treatment.)

[seadan83]

Not sure anything is captured. Need control for diet and measurements of existing creatine levels. It takes a few weeks to get creatine higher after supplementation. This is a small sample sized study that strikes me as dubious. Particularly compared to others that have done muscle biopsies. The pre-warm up routine is itself sus, that impacts lifting potentially more than creatine. Creatine also has a role in recovery, good luck measuring that..

[TomHenderson3]

In the introduction they talk about creatine loading. Also, their study is looking at lean body mass changes after the "wash-in" period, so any effect that increased recovery is supposed to have on lean body mass when following the exercise protocol they give for the time period they studied should be captured, no?

[seadan83]

> In the introduction they talk about creatine loading

(1) Yes, that the loading phase was BYPASSED. = (

"Those on creatine did bypass a loading phase, which includes taking 20 to 25 grams daily for up to one week. While it is common to start with a loading phase, it can cause gastrointestinal issues and is not necessary to reach saturation levels – the maximum that the body can store at any one time. "

My understanding, to reach saturation without a loading phase - it takes about 3 to 4 weeks. (Could be wrong, going off of memory there.)

With loading, I've read it takes 1 to 2 weeks to reach saturation.

(2) Without measuring creatine levels, what was even tested? How many people were creatine "non-responders?" How many people were getting plenty of creatine from their diets already?

(3) Was the creatine regimen effective and optimal? Water intake is another factor. I don't think a set of 50 people divided between 2 groups is going to be anywhere near enough to capture a nuance like efficacy of the regimen vs no regimen.

> Also, their study is looking at lean body mass changes after the "wash-in" period, so any effect that increased recovery is supposed to have on lean body mass when following the exercise protocol they give for the time period they studied should be captured, no?

I'd say no, simply because it is not known whether the wash-in period was actually a wash-in period without knowing if creatine levels actually changed in a significant way. Second, the study group of beginner weight lift lifters is a chaotic data set. The gains of lifting weights vs not lifting weights is likely magnitudes different from creatine vs no-creatine supplementation. Some beginners might easily get 10% more muscle mass vs 5% for others. An effect that is expected be very low is going to be completely lost in the noisy data. Let alone that we are starting from a questionable baseline.

Overall, since the body can absorb up to about 5g of creatine a day, and the body is likely already intaking 1 or 2g per day - this study is kinda only looking at the effect of an increase of creatine from a moderate dosage to a maximal dosage, across beginner weight lifters. It's like, say you're a bit dehydrated, instead of drinking 500ml of water per day, you now start drinking 550ml of water and then measure any changes from starting a brand new weight lifting routine.